41. The most common causes of hypoxemia are ventilation-perfusion mismatch, hypoventilation, and shunts. 42. It may be that increased perfusion to the brain and other organs also have indirect benefits. 43. In effect, the two arteries do not function as collateral perfusion to the watershed area. 44. Arterial hypoxemia in these patients has been attributed to ventilation-perfusion inequality and intrapulmonary shunting. 45. For example, rubidium chloride is used in isotopic labeling to evaluate perfusion of heart muscle. 46. Using radioactive microspheres is an older method of measuring perfusion than the more recent imaging techniques. 47. Greater discussion on the effect of blood perfusion on heat transfer is given in Section 2. 48. For perfusion experiments, an electrically powered roller pump was first used by Fleisch in 1935. 49. However, this may actually be advantageous for applications such as tumor perfusion and angiogenesis imaging. 50. The remaining channels are opened and constant perfusion and superfusion are adjusted using separate syringe pumps.
